An intravenous (IV) catheter apparatus of this kind is generally known and, for example, used to administer medicine to a patient or to take blood from a patient.
In use, the tubular catheter is inserted into a blood vessel of the patient, typically a vein, by means of the needle which will be withdrawn from the catheter after insertion of the tubular catheter into the blood vessel. When the needle tip enters the blood vessel, blood flows through a lumen of the needle into a needle hub provided at a proximal end of the needle, where it can be observed by the person handling the catheter apparatus. The event of blood entering the needle hub is called blood flashback and is used by the person handling the catheter apparatus to confirm venipuncture, from which point on the person inserts the catheter as far as desired under a decreased inclination of the needle in order to not puncture the back wall of the blood vessel.
In the case of delayed blood flashback there is a risk that the person handling the catheter apparatus continues to push the needle into the blood vessel under the increased original inclination of the needle until it exits at the rear side of the blood vessel. This second venipuncture represents a risk to the health of the patient as it may result in inner bleeding. Apart from that the catheter apparatus will have to be removed and replaced by a new one, i.e. the process of introducing the catheter will have to be repeated which is unpleasant and painful to the patient.